update for latest trunk changes

git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@14314 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
update testsuite

git-svn-id: http://caml.inria.fr/svn/ocaml/branches/ephemeron@14317 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02


git-svn-id: http://caml.inria.fr/svn/ocaml/branches/ephemeron@14318 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
first patch from Francois Bobot: add a new GC phase

git-svn-id: http://caml.inria.fr/svn/ocaml/branches/ephemeron@14319 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02